Microsoft has begun rolling out an optional preview update for Windows 11 that promises to make the Start menu and Search experience noticeably faster. The update, designated KB5089573, is available as of May 26, 2026, for systems running Windows 11 version 24H2 and the newer 25H2 release. At its core is a new "Low Latency Profile," a CPU scheduler behavior modification engineered to reduce input lag and improve responsiveness for key shell components.

The release comes as a welcome surprise for Windows enthusiasts who have long complained about occasional sluggishness in the Start menu and Search pane, particularly on systems under heavy load. While Microsoft has made incremental improvements to these UI surfaces over the past two years, KB5089573 represents a deeper, system-level optimization that targets the very way Windows allocates processor time.

What is the Low Latency Profile?

Although Microsoft has not yet published detailed documentation on the Low Latency Profile, the concept itself is not entirely new. Modern operating systems use sophisticated CPU schedulers to decide which threads get processor time and for how long. By default, Windows prioritizes a balance between foreground responsiveness and background throughput, ensuring that tasks like file indexing or Windows Update downloads don't starve interactive applications. However, this balance can sometimes leave milliseconds of latency on the table—tiny delays that, when accumulated, make clicking the Start button or typing a search query feel ever so slightly laggy.

KB5089573 appears to tweak the scheduler to grant an extra boost to threads associated with the Windows shell—the Start menu, taskbar, Search, and other interface elements. When a user interacts with these components, the system instantly elevates their priority, minimizing the time the CPU spends on less critical background work. The result is a more immediate visual and interactive response, akin to how gaming-oriented power plans or workstation tuning utilities can make a system feel more "snappy."

The update does not introduce a new power plan or user-facing setting. Instead, the Low Latency Profile operates transparently under the hood, activated automatically when the system detects shell interactions. This means that even on laptops running in "Balanced" or "Power Saver" mode, the Start menu should pop open without hesitation, and search results should appear as fast as you type.

The technical mechanics of CPU scheduling and foreground boosts

To understand why this matters, it helps to know how the Windows scheduler works. Each running program is made up of threads, and the scheduler parcels out CPU time in tiny slices called quanta. Threads have a base priority, but Windows can dynamically boost priorities for threads that are waiting for user input—a technique known as foreground or I/O priority boosting. Typically, the boost is modest to prevent starvation of background services.

With the Low Latency Profile, the boost for shell threads is both larger and more immediate. Instead of a gradual climb in priority, the thread responsible for rendering the Start menu animation might jump to a near-realtime priority for just a few hundred milliseconds. This ensures the UI thread runs with minimal delay, resembling how operating systems handle hardware interrupts. The key is that the boost is brief, so other tasks aren't meaningfully impacted.

Real-world impact: Start menu, Search, and beyond

Early adopters who installed the optional update report that the difference is most palpable when launching Start immediately after boot or resume from sleep—moments when system services often compete for CPU time. The Start menu's animation and live tile or widget updates now reportedly render without micro-stutters. Similarly, the Search flyout, which queries both local files and web results, surfaces suggestions with noticeably reduced typing-to-display latency.

But the benefits may extend beyond these two components. Since the scheduler adjustment targets the entire Windows shell process (explorer.exe and related modules), other interface elements could see indirect improvements. Right-click context menus, notification center expansions, and even the taskbar's overflow tray may feel more responsive. Microsoft's internal testing likely identified that the shell's main thread was occasionally being preempted by background tasks, leading to visible hangs. By giving it a temporary priority boost, the OS preserves the fluidity users expect.

It's important to note that the Low Latency Profile is not a silver bullet for all performance issues. Systems with slow hard drives, insufficient RAM, or underpowered CPUs will still struggle. The optimizations assume the hardware is capable but occasionally mis-scheduled. On modern SSDs and multi-core processors, however, this tweak could erase those frustrating split-second delays that mar the premium feel of Windows 11.

How to install KB5089573

As an optional preview update, KB5089573 is not pushed through Windows Update automatically. Enthusiast users eager to test the performance improvements can manually install it by navigating to Settings > Windows Update > Check for updates, and then clicking Download and install when the optional quality update appears. Alternatively, the update can be downloaded from the Microsoft Update Catalog for offline installation or deployment across multiple machines.

It's worth remembering that preview updates are essentially beta-quality releases intended for validation before being bundled into the next month's Patch Tuesday cumulative update. While Microsoft has tested the bits internally, they may still harbor unknown issues. The company has not flagged any critical bugs with KB5089573 as of this writing, but cautious users may want to wait for the general availability release in June 2026.

Verifying the Low Latency Profile is active

There is no direct toggle or system tray icon to indicate the Low Latency Profile is working. However, advanced users can use tools like Process Explorer to observe thread priorities before and after interacting with the Start menu. After installing KB5089573, you might notice that explorer.exe threads temporarily spike to a higher priority class when the Start menu is invoked. For most users, the only verification needed is a smoother, more responsive interface.

A history of chasing Start menu performance

The Start menu has been a focal point of performance criticism since Windows 11's debut in 2021. The original release, with its centered design and cloud-powered recommendations, often lagged behind its Windows 10 predecessor in raw responsiveness, especially on lower-end hardware. Microsoft responded with a series of patches throughout 2022 and 2023 that accelerated animations, reduced memory overhead, and improved the reliability of live updates for widgets. The so-called "Moment" updates also introduced algorithmic tweaks to search indexing, making file lookups faster.

KB5089573 takes a different tack. Rather than optimizing the application code itself, it adjusts fundamental OS scheduling behavior. This approach harks back to the days of Windows 7, when foreground priority boosts and UI thread prioritization were actively tuned per release. With the ever-growing complexity of modern Windows—running hundreds of processes and services—such low-level tuning has become necessary once again to maintain a fluid user experience.

The broader picture: Windows 11's performance pledges

Microsoft has increasingly emphasized performance and quality as key pillars of Windows development. Under the leadership of the Windows and Devices chief, the team has committed to making Windows 11 feel "fast and fluid" on all supported hardware. Recent updates have trimmed the disk footprint, accelerated login times, and reduced the system's impact on battery life. The Low Latency Profile fits neatly into this strategy, addressing the perceptive performance—how the OS feels moment-to-moment—rather than just benchmark scores.

It's also a sign that Microsoft is willing to revisit long-standing scheduler conventions. Historically, the Windows scheduler has been conservative in promoting thread priorities to avoid starvation of background services. The introduction of a shell-specific latency profile suggests that the company has gathered enough telemetry data to confidently identify which tasks can be temporarily deprioritized without causing system instability.

Potential caveats and known issues

While the community response has been largely positive, some advanced users have raised valid questions. For instance, could the priority boost inadvertently delay critical background services? In theory, aggressively prioritizing the shell thread could cause brief pauses in file transfers, network activity, or rendering tasks. However, Microsoft's implementation likely applies a very short-lived boost—perhaps on the order of a few hundred milliseconds—just enough to ensure the UI responds instantly without meaningful detriment to other workloads.

There are also reports that the update resets some custom power profile settings, as it updates the underlying power management infrastructure. Users who have meticulously tuned their processor power management, PCI Express power saving, or background throttling via command-line tools should double-check their configurations after installing KB5089573.

Another nuance is that the Low Latency Profile might not fully activate on all hardware configurations. Systems with heterogeneous CPU architectures, such as Intel's 12th-gen and newer processors with P-cores and E-cores, may see different behavior because the thread director and scheduler interplay is more complex. Microsoft likely validated the feature on a wide range of devices, but edge cases are possible.

Battery life considerations

Because the priority boosts are temporary and only occur during shell interactions, the impact on battery life should be negligible. The update does not force the CPU to run at higher frequencies; it merely reorders existing workloads. Laptop users can expect the same endurance as before, with the added benefit of a more responsive interface.

Conflicts with third-party tuning tools

Some users rely on utilities like Process Lasso or power plan customizers to enforce specific scheduling behaviors. These tools may override or conflict with the Low Latency Profile. If you experience erratic behavior after installing KB5089573, try temporarily disabling such software to see if the issue resolves.

What to expect in future updates

Assuming the preview yields positive telemetry and user feedback, the Low Latency Profile should graduate to a mandatory cumulative update in June 2026. Beyond that, it may serve as a foundation for even more aggressive UI optimizations. Microsoft engineers have hinted in various development forums that they are exploring per-application latency targets, which would allow demanding real-time applications—like digital audio workstations or VR compositors—to request guaranteed low-latency scheduling.

For now, KB5089573 is a targeted but welcome enhancement that demonstrates Microsoft's attention to the "little things" that collectively define Windows 11's user experience. A faster Start menu and Search might not make headlines like a new AI assistant or revamped File Explorer, but it's the kind of polish that keeps the OS feeling modern and responsive.

How to provide feedback

Users who install the optional update can share their experiences directly with Microsoft via the Feedback Hub (Win + F) under the category Desktop Environment > Start menu. The company actively monitors this channel to catch regressions and gauge sentiment. If you notice any new stutters, crashes, or unintended side effects, reporting them with detailed reproduction steps helps refine the feature before its mandatory rollout.

Conclusion

KB5089573 is more than a routine bug-fix; it's an understated performance tune-up that addresses a long-standing wish from the Windows community: a consistently fast Start menu and Search. By introducing a Low Latency Profile at the scheduler level, Microsoft is delivering on its promise of a fluid, responsive operating system without requiring users to fiddle with settings. Whether you install the preview now or wait for the official patch, the end result should be a Windows 11 that feels just a bit more eager to keep up with your clicks and keystrokes.